Method and apparatus for contracting and compressing fibre shells



June 30, 1959 METHOD AND APPARATUS Filed June 4, 1956 H. L. CARPENTER FOR CONTRACTING AND COMPRESSING FIBRE SHELLS 2 Sheets-Sheet 1 INVENTOR far wafer Md 1 M ATTORNEY June 30, 195 H. CARPENTER METHOD AND APPARATUS FOR CONTRACTING AND COMPRESSING FIBRE SHELLS Filed June 4, 1956 2 Sheets-Sheet 2 ATTORNEYS United States Patent 2,892,749 I METHOD AND APPARATUS FOR CONTRACTING AND COMPRESSING FIBRE SHELLS Herbert L. Carpenter, Amityville, N.Y., assignor to The Greif Bros. Cooperage Corporation, Delaware, Ohio, a corporation of Delaware Application June 4, 1956, Serial No. 589,026 2 Claims. (Cl. 154-83) This invention relates to an improved method and apparatus for making tubular fibre shells having reduced flange portions.

Tubular shells made from fibre are frequently used as containers and enclosures for packing and shipping articles and materials. At times, it is desirable to provide such shells with a section of reduced diameter as, for instance, with a reduced flange at one or both ends thereof. The reduced flange may serve to receive a cover member, a coupling member or another tubular shell section. The formation of such reduced flange sections presents difiiculties since the forming of the fibrous material in this fashion generally weakens, damages or ruptures the fibres.

It is an object of the present invention to overcome these difficulties and to provide an improved method and apparatus for providing tubular fibre shells such as fibre containers with reduced flange portions which are as strong or stronger than the body of the shell and in which the fibrous material is not weakened, damaged or ruptured.

A further object of the invention is the provision of an improved method and apparatus of the above character which can be used in forming reduced flange portions on tubular fibre shells in a simple, eflicient and inexpensive manner and which lend themselves to commercial, modern, mass production methods.

My invention contemplates forming a section of a freshly made tubular fibre shell, in which the adhesives of the laminated layers have not yet set, into a flange portion of reduced diameter and reduced wall thickness by applying to one surface of the section pressure at a temperature in excess of the boiling point of the liquids in the adhesive and by applying to the other surface of the section pressure at a temperature somewhat lower than the boiling point of the liquid.

In the accompanying drawings- Fig. 1 is a sectional elevational view of one form of apparatus embodying my invention and which may be used in performing my method for contracting and compressing fibre shells. In Fig. 1 the dies are shown partially in open position with a tubular fibre shell disposed around the male die member;

Fig. 2 is a similar longitudinal sectional View of the upper portion of the apparatus but showing the dies in closed position with the end portion of the shell formed into a flange of reduced diameter and reduced wall thickness;

Fig. 3 is a transverse sectional View of the apparatus in the direction of the arrows on the line 33 of Fig. 1;

Fig. 4 is a longitudinal sectional view of a tubular fibre shell in the form of a fibre drum having a reduced flange portion at one end made in accordance with the present invention;

Fig. 5 is a longitudinal sectional view of another form of tubular fibre shell in the form of a drum or container having a reduced flange portion at both ends made in accordance with the present invention;

Fig. 6 is a perspective view of another modified form of tubular shell of non-cylindrical shape having a reinvention; and

"duced flange portion made in accordance with the present Fig. 7 is a sectional plan view of a modified form of die which may be used in apparatus embodying my invention.

My invention is applicable to various types of tubular fibre shells particularly shells made from convolutely wound or spirally wound layers of kraft paper, or other suitable fibre laminated together by adhesives. In the manufacture of shells of this type adhesives are applied to a surface of the fibre and the fibre is wound around a mandrel of suitable size until the desired wall thickness has been obtained. The shell thus formed is then removed from the mandrel. A freshly formed shell in which the adhesives are still wet and have not as yet set may be more readily formed and shaped without weakening, damaging or rupturing the fibres and in carrying out my invention I use a freshly formed shell.

In Figs. 4, S and 6 I have shown tubular fibre shells in the form of containers in which portions of reduced diameter have been provided in accordance with my invention. Thus, in Fig. 4 I have shown a fibre drum or container 10 having a tubular cylindrical body portion 11 made from convolutely wound layers of fibrous material such as kraft paper and having a flange portion 12 near its upper end of reduced diameter and reduced wall thickness. Due to the reduced wall thickness, the material in the flange 12 is relatively more compressed and more compact than the fibrous material in the remainder of the tubular shell. Fitted over the reduced flange portion of the container is a closure, as for instance, a head 14 having a circular top portion 15 resting on the upper end of the flange and secured by staples or stitching 16 to an apron portion 17 which fits over the flange. The outside diameter of the body portion of the container and the outside diameter of the apron portion of the closure are substantially equal so that when the head is applied the container assembly presents a smooth cylindrical appearance from top to bottom. The two surfaces of the top of the closure may be covered with sheets 18 laminated thereto and made of suitable material to serve as protective or ornamental coverings or seals. The closure itself may be made of any desired material such as fibre, wood or metal. The bottom of the container is provided with a suitable closure, such as the disk shape member 19 which likewise may have covering sheets 20 applied thereto. The bottom closure is suitably secured in place as by means of folding the lower edge of the shell inwardly as shown at 21 and securing it to the closure by suitable means, such as stitching or staples, as shown at 22.

In Fig. 5, I have shown a container 30 having a convolutely wound cylindrical fibre body portion 31 with flanges 32 and 33 of reduced diameter and reduced wall thickness formed at both the upper and lower ends thereof. A head 34 of modified design is shown as applied to the upper flange 32. In this form of head, the top portion 35 is shown as disposed inside of the flange in the form of a plug and it is secured by stitching or staples 36 to the apron portion 37 which overlaps the top of the flange and depends downwardly in engagement with the outer surface thereof. A suitable ornamental or protecting sheet or seal 38 may be applied to one or both surfaces of the top as shown. The bottom of the container 30 is suitably closed as by means of a bottom closure 39 permanently secured in place by folding the lower portion of flange 33 inwardly, as shown at 41, and securing it to the closure by suitable stitching or staples 42.. Ornamental or protecting sheets or seals may similarly be applied to one or both surfaces of the bottom closure as shown at 40.

In Fig. 6, I have shown a further modified form of fibre shell in the form of a tubular container 50 of noncylindrical shape. The container shown in Fig. 6 is substantially rectangular in cross-section but it should be noted that the corners are rounded or arcuate and the side edges are transversely curved or convex. The container 50 has a body portion 51 and a flange 52 of reduced diameter and reduced wall thickness at its upper end.

The container shown in Figs. 4, 5 and 6 are represen tative types of shells to which my invention is applicable. It should be understood that my invention may be ap plied to tubular fibre shells of any desired cross-sectional size or shape and to fibre shells which are either convolutely or spirally wound. With this in mind, we now refer to Figs. 1, 2 and 3.

When the fibre shell is first wound it is of uniform diameter or of uniform cross-sectional size from end to end. A freshly wound shell of this type is formed in accordance with my invention, in order to provide the flange portions of reduced diameter and of reduced wall thickness, by applying deforming pressure at a temperature above the boiling point of the solvents to one surface of the portion of the shell to be treated and by applying backing pressure at a temperature lower than the boiling point to the opposite surface so as to limit the deformation to the desired amount. By thereafter continuing the deforming pressure the fibrous material can be compressed and the wall thickness reduced. When the desired reduction in diameter and wall thickness has been obtained, the heat and deforming pressure is first removed, and thereafter the backing pressure is removed.

The adhesives used in laminating the layers of the shell together usually include liquid solvents and among the liquid solvents employed is water. Thus, the temperature to be applied to one surface of the formed area of the shell should be in excess of 212 F. and I have found that very satisfactory results are obtained at 400 F. The temperature to be applied to the opposite area of the shell to be formed should be less than 212 F. and I have found that very satisfactory results are obtained by maintaining the temperature of this surface substantially below 212 F. The pressure should, of course, be applied in such a manner as to deform the shell wall to the desired shape and thickness and I have found that the heat should be applied to the surface of the drum to which the deforming pressure is applied, while the low temperature should be applied to the surface of the drum to which the backing pressure is applied. Where a flange of reduced diameter and wall thickness is formed, the heat and deforming pressure are applied to the outer surface of the shell and the backing pressure and low temperature are applied to the inner surface of the shell.

In Fig. l, I have shown a freshly made tubular fibre shell 55 of uniform diameter and cross-sectional size from end to end. The pressure and temperature may be applied by any suitable means.

In Figs. 1 to 3, I have shown a pair of dies consisting of an internal male die or core 56 which supports the shell wall and provides suitable backing pressure and an external female die '57 which is heated to the desired temperature and provides deforming pressure to the outer surface of the shell. The internal die is preferably of the expanding and contracting type and in the illustrated embodiments consists of a pair of semi-cylindrical segments 58, supported on threaded flange member 59 on the upper end of tubular standard 60. The segments are supported on the flange member so that they may shift inwardly and outwardly to contract and expand the die. Thus, the attaching screws 61 may pass through slots formed in the flange member, as shown, so as to permit relative shifting.

Suitable mechanism is provided for expanding and contracting the die and this may take the form of links 62 pivoted to the inner surfaces of the die segments 58 at diametrically opposite sides thereof and also pivoted to the shiftable rod 63. The rod 63 extends vertically downwardly through the tubular standard 60 and is shiftably supported in spider members 64. When the rod is in its uppermost position, as shown in Fig. 1, the links are horizontally disposed and the internal die 56 is in its expanded position. When the rod 63 is shifted downwardly the links 62 are angularly disposed and pull the die sections inwardly to contracted position thereby facilitating the assembling of the shell around the die and the removal of the shell after the flange has been formed.

The rod 63 may be shifted manually or by suitable power mechanism, such as the hydraulic or pneumatic cylinder 65 having a reciprocating piston (not shown) therein. The lower end of the piston rod 66 is pivotally connected to a lever 67 fulcrumed to the tubular standard 60, as shown at 68, and pivotally connected at its opposite end to the lower end of rod 63, as shown at 69.

The internal die 56 is preferably cooled in some suitable fashion and for this purpose the segments 58 may be hollow and formed with chambers 70 therein through which a cooling fluid may be circulated. The cooling fluid may be introduced through a tube 71 extending upwardly through the standard 60 and connected to the chamber in one of the segments 58. The cooling fluid may be circulated from one chamber to another through the tubes 72 connected between the chambers in the segments as shown. The tubes 72 are fixedly secured to one of the segments and have a slip or slide connection with the other segment passing through packing rings 73 so that no leakage can take place. This permits the die to be contracted and expanded. The cooling fluid is withdrawn from the second segment by means of tube 73 having connection to the chamber in the segment near the upper end thereof as shown.

The shell 55 may be suitably supported as on a platform 74 adjustably secured to the tubular standard 60 by a set screw 75.

The internal die 56 is shaped so as to provide backing support of the desired contour. Thus, where it is desired to provide a flange of reduced diameter and reduced wall thickness near one end of the shell, the lower portion of the die, when expanded, should be large enough to engage and support the body of the shell. Above the lower portion, the die tapers inwardly, as shown, and terminates at its upper end in a reduced portion 76 corresponding to the desired internal diameter of the restricted portion of the shell. The die and shell, when assembled together, should be arranged so that the upper ends of both the die and shell terminate at about the same level.

The external die or female die in the apparatus shown in Figs. 1, 2 and 3 is shiftable vertically so as to permit the shell to be assembled with the lower die and to be removed therefrom. Thus, the die 57 may be supported at the lower end of shiftable rod 80 by suitable threaded studs 81. The external die is likewise shaped to conform with the desired shape and contour of the finished shell. Thus, it has a lower portion 82 of enlarged diameter conforming with the external diameter of the shell body. The lower portion tapers inwardly at 83 to connect with the restricted upper portion 84 of reduced diameter corresponding with the desired external diameter of the flange portion of the shell.

When the external die is shifted downwardly from the position shown in Fig. 1 to the position shown in Fig. 2 it will cause the upper end portion of the shell to be reduced in diameter and in wall thickness. This is due to the fact that the spacing between the upper portion 84 of external die 57 and the upper portion 76 of internal die 56 is less than the wall thickness of the shell as originally formed. The external die 57 may be heated in suitable fashion as by means of the heating elements 85 extending therearound. In this connection, the temperature may be automatically controlled by means of the the mometer and thermostat indicated at 86.

In using the apparatus shown in Figs. 1 to 3 the shell is first assembled around the internal die as shown in Fig. 1, the coolerant is circulated through the lower die so as to maintain the temperature substantially below 212 F. and the heating element is energized in the external die so as to heat it above 212 F. The shell assembled with the die should be freshly made so that the solvents are fluid and workable and so that the fibrous material is soft, pliable and workable. When the upper die has been properly heated above 212 F., preferably in the neighborhood of 400 F., it is shifted downwardly to the position shown in Fig. 2, with the result that it applies deforming pressure at a temperature substantially above 212 F. preferably in the neighborhood of 400 F. to the exterior surface of the shell at the upper end thereof where the flange is to be formed. This portion of the shell is deformed inwardly against the internal die which provides backing pressure to prevent deformation beyond the desired amount. The internal die is cooled so that the backing pressure is applied at a temperature substantially below 212 F. It will be seen that the spacing between the dies is such that the deforming pressure and backing pressure not only contract the shell but also compress the fibres and reduce the wall thickness. When the shell has been thus deformed the upper die is elevated so as to first remove the deforming pressure and thereafter the internal die may be contracted to permit the shell to be removed therefrom.

I have found that by heating the deforming die, the freshly formed fibrous shell can be readily formed without weakening, damaging or rupturing the fibres. I have also found that by cooling the backing die I prevent the solvent vapors from bursting or rupturing the fibrous materials particularly when the deforming pressure is first removed.

In Figs. 1 to 3, I have shown one type of die structure which may be used in carrying out my invention. Various die structures may be employed for this purpose. Thus, in Fig. 7 I have shown a modified type of external die which expands and contracts to apply deforming pressure to the desired area of the shell.

In the apparatus shown in Fig. 7, I employ an internal male die 56 similar to that shown in the first form of my apparatus and around which the fibre shell 55 is disposed. The external die is shown generally at 90 and instead of shifting vertically, as in the first form of my invention, it is composed of a plurality of segments 91 which expand and contract. In the form of my invention shown in Fig. 7 I have illustrated six separate segments each having a separate electric heating element 93 so as to heat the external die to a temperature above the boiling point of the solvent.

The expansion and contraction may be controlled by any desired mechanism. Thus, as an example, I have shown a plurality of hydraulic cylinders 93 having reciprocating pistons therein. Hydraulic fittings 94 and 95 serve to introduce hydraulic fluid and remove it from the cylinder. In Fig. 7, the external die is shown in contracted position so as to contract and compress the flange of the shell 55.

In using the apparatus shown in Fig. 7 the shell is first assembled around the internal die 56 while the external die 90 is in expanded condition. The external die is heated to the desired temperature and the internal die is cooled. Thereafter, the cylinders 93 are operated so as to cause the segments 91 to shift inwardly to contract the die and thereby contract and compress the flange portion of the shell. Thereafter, the external die is expanded. Thereafter, the internal die is contracted and the shell is removed therefrom.

It will be appreciated that the dies may be arranged so as to contract and compress any portion of the shell wall such as the upper or the lower flange portions, as shown in Figs. 4, and 6. In addition, the tubular shell, which is thus treated in accordance with my invention, may be of any desired cross-sectional shape such as circular, as shown in Figs. 4 and 5, or modified rectangular as shown in Fig. 6. When the portion of the shell has been contracted and compressed, in accordance with my invention the shell may be formed into a container such as shown in Figs. 4, 5 and 6.

I have found that a shell having a contracted portion made in accordance with my invention has the advantage that the fibres are not weakened, damaged or ruptured in any respect and as a matter of fact the flange portion is at least as strong, if not stronger, than the remainder of the shell. This is due in part to the fact that the fibres are not broken or exploded during treatment and in addition the flange portion is not only reduced in diameter but is also compressed or compacted.

Modifications may, of course, be made in the illustrated and described embodiments of my invention Without departing from the invention as set forth in the accompanying claims.

I claim:

1. The method of forming a tubular fibre shell with a portion of restricted diameter by means of an internal or male die and an external or female die which comprises: first providing a tubular fibre shell of uniform diameter from end to end made from layers of convolutely wound fibrous material laminated together by an adhesive having a liquid solvent, said shell being in freshly made condition prior to the setting of the adhesive and while the solvents are still wet; maintaining the said female die at an elevated temperature above the boiling point of the adhesive solvents and while said shell is still in such freshly made condition applying a deforming pressure to the outer surface of the portion of the shell which is to be restricted by means of said female die while maintained at said elevated temperature so as to vaporize the solvents and deform the said portions of the shell inwardly; and maintaining said male die at a temperature substantially below the boiling point of the adhesive solvents by means of a coolant and while said shell is still in such freshly made condition applying a backing pressure to the inner surface of said portion of the shell by means of said male die while thus maintained at a temperature substantially below the boiling point of the adhesive s01- vents so as to limit the deformation to the desired amount while continuing the application of deforming pressure at an elevated temperature 'to the outer surface of said portion of the shell so as to compress the fibrous material and reduce the wall thickness.

2. The method of forming a tubular fibre shell with a portion of restricted diameter by means of an internal or male die and an external or female die as set forth in claim 1 in which the application of the deforming pressure by means of the female die while maintained at a temperature above the boiling point of the adhesive solvents is discontinued prior to the discontinuance of the application of the backing pressure.

References Cited in the file of this patent UNITED STATES PATENTS 666,812 Laraway Jan. 29, 1901 735,778 Kenney Aug. 11, 1903 1,128,785 House Feb. 16, 1915 1,133,913 Beadle Mar. 30, 1915 1,436,643 Bolger NOV. 28, 1922 2,066,991 Lutz Jan. 5, 1937 2,255,116 Helmstaedter Sept. 9, 1941 2,295,855 Ludwell Sept. 15, 1942 2,417,226 Weyant Mar. 11, 1947 2,419,864 Westin Apr. 29, 1947 2,478,943 Rhodes Aug. 16, 1949 FOREIGN PATENTS 924,825 France Mar. 17, 1947 

1. THE METHOD OF FORMING A TUBULAR FIBRE SHELL WITH A PORTION OF RESTRICTED DIAMETER BY MEANS OF AN INTERNAL OR MALE DIE AND AN EXTERNAL OR FEMALE DIE WHICH COMPRISES: FIRST PROVIDING A TUBULAR FIBRE SHELL OF UNIFORM DIAMETER FROM END TO END MADE FROM LAYERS OF CONVOLUTELY WOUND FIBROUS MATERIAL, LAMINATED TOGETHER BY AN ADHESIVE HAVING A LIQUID SOLVENT, SAID BEING IN FRESHLY MADE CONDITIONS PRIOR TO THE SETTING OF THE ADHESIVE AND WHILE THE SOLVENTS ARE STILL WET; MAINTAINING THE SAID FEMALE DIE AT AN ELEVATED TEMPERATURE ABOVE THE BOILING POINT OFX THE ADHESIVE SOLVENTS AND WHILE SAID SHELL IS STILL IN SUCH FRESHLY MADE CONDITIONS APPLYING A DEFORMING PREASURE TO THE OUTER SURFACE OF THE PORTION OF THE SHELL WHICH IS TO BE RESTRICTED BY MEANS OF SAID FEMALE ID WHILE MAINTAINED AT SAID ELEVATED TEMPERATURE SO AS TO VAPORIZE THE SOLVENTS AND DEFORM THE SAID PORTIONS OF THE SHELL INWARDLY; AND MAINTAINING SAID MALE DIE AT A TEMPERATURE 